Earth

“Just a couple of guys we seem to have picked up in open space,”
she said. “Section ZZ9 Plural Z Alpha.”

The Hitchhiker's Guide to the Galaxy, Chapter 11

Although the primitive ape-descended denizens of this planet did not realize
it, the Earth was designed by a supercomputer called Deep Thought, and was built
by the Magratheans. Slartibartfast
won an award for his fjords on the coast of Norway.

The Earth was actually a computer so vast that organic life became part of
it's matrix.

IIt was destroyed by the Vogons five
minutes before the completion of its program.